This invention relates to composite extrusion, especially to side-by-side extrusion.
Forming a composite stream, in particular a side-by-side composite stream, is well known. Exemplary patents include U.S. Pat. Nos. 4,348,346 to Thompson, 4,533,510 to Nissel, 4,731,004 to Wenz, Jr., 4,784,815 to Cloeren and Wernery, Jr., and 5,120,484 to Cloeren. Mechanically dividing a manifold using an adjustable block, is illustrated by the Nissel patent.
Control of the degree of overlap or intermix along the joined edges of adjacent flow streams, and control of the position of the joined edges across the composite stream width have been described. Particularly described are the effect of the location selected for the convergence locus and the effect of the relative flow volumes on control of these properties.
An extrusion apparatus having deckles controlling stream flow within the apparatus and defining the exit slot width and hence product width, is well known. The deckles may be internal, external, or an external/internal combination. The deckles may be precise or snug fitting blockage devices termed "deckle plugs". Illustrative patents include U.S. Pat. Nos. 3,018,515 to Sneddon, 4,057,385 to Yazaki et al and 4,659,302 to Maejima et al, and UK Patent Application No. 2,114,050.
However, there remains a need for an improved extrusion apparatus capable of composite extrusion and product width adjustment.